US appeals court refuses Arzerra rehearing

Biotechnology company Genmab A/S announced on July 15 that the US Court of Appeals for the Federal Circuit has refused a request to rehear a case related to its Arzerra product.

Arzerra is given as an injection used in the treatment of CLL. It is made with the active ingredient ofatumumab, a monoclonal human antibody for the CD20 protein.

Genmab develops Arzerra as part of a co-development and commercialisation agreement with GlaxoSmithKline (GSK), which received approval to market the drug from the US Food and Drug Administration in 2009.

In 2010, Genentech Inc, a member of the Roche group, and Biogen Idec Inc filed the  original lawsuit against GSK at the US District Court for the Southern District of California.

They alleged Arzerra infringes their US patent  7,682,612, which covers methods of treating chronic lymphocytic leukaemia (CLL) with anti-CD20 antibodies.

GSK claimed that it did not infringe the patent, and that the patent was invalid.

After the district court ruled in GSK’s favour in December 2011, Genentech and Biogen appealed against the decision at the US Court of Appeals for the Federal Circuit.

They claimed the district court’s construction of the term “anti-CD20 antibody” was narrowed based on prosecution history disclaimer.

The district court’s decision was later  upheld by the appeals court, and in May 2013, Genentech and Biogen requested a re-hearing en banc.